"Great scientific discoveries are like sunrises," says E. O. Wilson. First they touch just the tips of a few peaks and steeples; then they illuminate the whole world.

The greatest discoveries change everything for us, says James D. Watson: not only our feelings about science, "but about existence."

No discovery has changed us more than Charles Darwin's. Now, thanks to a publishing coincidence, we have not one but two new Darwin readers, one introduced by Wilson, the other by Watson--two of the world's best-known biologists since Darwin. Each volume reprints the same classics: Darwin's Voyage of the Beagle, On the Origin of Species, Descent of Man, and Expression of the Emotions in Man and Animals. Each volume even carries the same epigraph. It is the final sentence from Descent, the sentence in which, after decades of dread and delay, Darwin finally allowed himself to drive his idea all the way home: "We must acknowledge, as it seems to me, that man with all his noble qualities, with sympathy which feels for the most debased, with benevolence which extends not only to other men but to the humblest living creature, with his god-like intellect which has penetrated into the movements and constitution of the solar system--with all these exalted powers--Man still bears in his bodily frame the indelible stamp of his lowly origin."

I've been dipping into these two volumes, rereading Darwin with Wilson's and Watson's commentaries. Like everyone who follows biology, I've read all three men for years. And to me the most interesting thing about this little publishing coincidence is the larger coincidence that these three biologists, who succeeded in opening up new views of life, have also been brilliantly successful popular writers.

Darwin's first book, the story of his five-year voyage around the world as a young man onboard the HMS Beagle, was a best-seller in 1845, even though it said virtually nothing about evolution by natural selection, the great discovery he had begun to incubate in secret. Origin was such a success in 1859 that the first printing sold out before publication, as Watson says in his introduction, "no fewer than one-third being bought by Mudie's Circulating Library, an endorsement of the likely popularity of the book equivalent to a recommendation today from Oprah Winfrey." Even Darwin's last book, a study of earthworms, which he published in 1881, the year before he died, was a surprise best-seller--by Victorian standards, at least. "My book has been received with almost laughable enthusiasm," he wrote, "and 3500 copies have been sold."

In 1953, almost a century after Origin, the young James Watson stood over his sister's shoulder as she typed up a 900-word research paper he had written with his friend Francis Crick about the structure of DNA. "There was no problem persuading her to spend a Saturday afternoon this way," Watson wrote afterward, "for we told her that she was participating in perhaps the most famous event in biology since Darwin's book." The Double Helix, Watson's memoir of his discovery, was a best-seller, too.

As for Wilson, his book Sociobiology caused a scandal in 1975 by speculating about the evolution of human instincts in the same style in which it analyzed the evolution of instincts in bees, wasps and ants. Since then, his skills as a writer have won him two Pulitzer Prizes and an audience as wide as Watson's. Not that the two men have always gotten along. In Wilson's memoir, Naturalist, he devotes a chapter to the period in the 1950s and 1960s when he and Watson were young biology professors at Harvard. Wilson writes, "I found him the most unpleasant human being I had ever met."